☎️ Set up MaxiConnect SIP Trunk (MaxiTrunk) in 3CX

Step-by-step guide to connect MaxiTrunk (MaxiConnect SIP trunk) to your 3CX system: SIP settings, authentication, inbound DID rules, outbound routes and troubleshooting tips.

Prerequisites

Before you begin, make sure you have:

  • Administrator access to your 3CX console
  • Your MaxiConnect SIP credentials (server, username, password)
  • Your DID number(s) (assigned phone numbers)

Don’t have your SIP credentials yet? Contact MaxiConnect at +41 58 521 32 00.

Step 1 — Access the 3CX console

  1. Log in to your 3CX administration console
  2. In the left menu, go to SIP Trunks
  3. Click + Add SIP Trunk

Step 2 — Select the trunk type

  1. In the provider list, choose Generic SIP Trunk
  2. Click Next

Step 3 — General settings

FieldValue
NameMaxiConnect (or another descriptive name)
Registrar/Proxy serverMaxiConnect SIP server
Main numberYour main phone number
Number of simultaneous linesAs per your contract

Step 4 — Authentication

FieldValue
Authentication typeDigest
Authentication ID (Auth ID)Your SIP number or provided login
PasswordProvided SIP password

Step 5 — Advanced settings

In the Advanced Options tab:

ParameterRecommended value
TransportUDP (or TCP if recommended)
Port5060
Re-registration3600 seconds
Preferred codecG.722, then G.711

Enable “Send Keep-Alive” if your connection is behind a strict NAT.

Step 6 — Inbound rules (DID)

  1. Go to Routing Rules → Inbound Rules
  2. Add a new rule:
    • DID/Number: your phone number (international format without +)
    • Destination: extension, call group or IVR according to your configuration
  3. Repeat for each additional DID number

Step 7 — Outbound rules

  1. Go to Outbound Rules
  2. Verify that a rule exists routing external calls via the MaxiConnect trunk
  3. Example of a basic rule:
    • Dialling prefix: 0 or empty
    • Strip prefix: according to your configuration
    • Trunk: MaxiConnect

Testing the configuration

Once the trunk is configured:

  1. Make a call from an extension to an external number → check audio quality
  2. Call your DID number from a mobile phone → check that the call comes through
  3. Check the 3CX logs to diagnose any registration issues

Common issues

Trunk in “Not Registered” state → Check the SIP credentials (copy-paste exactly, no spaces) → Verify that port 5060 UDP is open on your firewall

One-way or dropped audio → NAT issue. Enable STUN in 3CX or configure NAT correctly

Inbound calls not ringing → Check the DID rules and that the number matches exactly the expected format

Technical support: +41 58 521 32 00 — hello@maxiconnect.ch

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